<section class="sec">
    <div class="row">
        <div class="col-md-12 pos">
            <div class="col-md-3 col-md-offset-1">
                <a href="">
                    <img src="img/zhihu_logo.jpg" alt="" class="img-responsive logo_desc"/>
                    <span class="text-capitalize desc">知乎</span>
                </a>
            </div>
            <div class="col-md-3 ">
                <a href="">
                    <img src="img/weibo_logo.jpg" alt="" class="img-responsive logo_desc"/>
                    <span class="text-capitalize desc">微博</span>
                </a>
            </div>
            <div class="col-md-3">
                <a href="">
                    <img src="img/douban_logo.jpg" alt="" class="img-responsive logo_desc"/>
                    <span class="text-capitalize desc text-center">豆瓣</span>
                </a>
            </div>
        </div>
    </div>
</section>